Process of producing concentrated nitric acid.



PATENT OFFICE.

BIRGER FJELD 1lALVORSEN,' OF GHRISTIANIA, NORWAY.

rnocnss F PRODUCING GONCEN'TRATED NITRIC ACID.

Specification of Letters Patent.

Patented July 7 1908.

Application filed February 9, 1906. Serial No. 800,280.

To all whom "it may concern:

Be it known that I, BIRGER' FJELI) HAL- VORSEN, a subjectof the King ofNorway, residing at Christiania, Norway, have invented certain new anduseful Improvements in Processes of Producing Concentrated Nitric Acid;and I do hereby declare the following to be a full, clear, and exactdescription of i the invention, such as will enable others skilled inthe art to which it appertains to make and use the same.

My invention relates to the )roduction of nitric acid and the sulfuricaci and consists in an improved method of the production of concentratednitric and concentrated sulfuric acid from nitroso sulfuric acid ornitrosyl sulfuric acid.

By several chemical rocesses diluted nitrous gases are obtaine for examle by the different methods of chemically binding the nitrogen of theair by means of the electric arc. Such nitrous gases, the rincipal oneof which is nitric oxid, may be a sorbed b sulfurous acid, in which casenitroso su furic acid is obtained or they may be'directly absorbed byconcentrated sulfuric acid in absorption towers (as in the Gay-Lussactower used in manufacturing sulfuric acid). It has not hitherto beenpossible to obtain nitric acid from such nitroso sulfuric acid or fromnitrosyl sulfuric acid except by a denitrifying process by which dilutedacids are obtained.

The object of my present invention therefore is to produce in anadvantageous Way concentrated nitric acid and concentrated sulfuric acidfrom nitroso sulfuric acid or.

from the nitrosyl sulfuric acid.

My method consists in dissolving the nitrous acid or the nitrososulfuric acid in a surplus of concentrated sulfuric acid, addingtilledoff in retorts of cast iron and the oxidizing substance regained byelectrolysis.

Before the electrolytic process takes place the solution is diluted withwater in sufficient quantity necessary for the electrolytic oxidatron.

The electrolytic oxidation may for example be effected as follows:

When the oxidizing substance has been regained a certain quantity of thesulfuric acid corresponding to the production is taken away, the rest ofthe sulfuric acid together with the oxidizing substances being utilizedagain for the oxidation of another quantity of nitrous acid. Thehydrogen obtained may be used in any suitable way or it may be utilizedat once in the electrolytic apparatus by introducing into theelectrolytic cell for example, salts of co per, in which caseelectrolytic co per is o tained. The oxidation ma also e effected bymeans of ozone WhlOh is led into the nitroso sulfuric solution. It isobvious that also in this case the necessary quantity of water has to beadded.

When ozone or peroxid of hydrogen are used a regeneration of oxidizingsubstance will not take place.

I claim.

1. The process which com rises dissolving sulfuric acid containing oxi sof nitro en in sulfuric acid, treating the obtained solution with anoxid of a metal capable of oxidizing the oxids of nitrogen, evaporatingthe nitric acid formed and re enerating the oxidizing agent by means ofe ectrolysis.

2. The process which corn rises dissolving sulfuric acid containing oxis of nitrogen in sulfuric acid, treating the obtained solution with apowerful oxidlzing agent, evaporizing the nitric acid formed,regenerating the oxidizing agent by means of electrolysis andsimultaneously treating a salt of a metal capable of electrolysis to theelectrolyte for the purpose of obtaining a valuable metal on the cathodeas a b product by the reducing ac- .tion of the hy ro en liberatedduring the recovery of the oxi izing agent.

3. The process wlnch comprises dissolv-' ing gulfuric apid. ecu 1minoiid bfnitro my invention; 1 have signed my flame in in m Sllflll'fi)acig, tfreaitring the solution so presence of twa subscribing witnesses.o taine .Wit oxi o c omium :evaporata ing the nitric acid formed,andjrecovering 33 HALVORSEN' 5 the oxid of' chromium, substantlally asde- Witnesses:

scribed.- HENRY Bormmwwn,

In testimony that I qlaim th feiggoifig :zts Jon. -VAALER.

